Measurement Of Exhaled Nitric Oxide Research Articles

Beyond the Runway: Respiratory health effects of ultrafine particles from aviation in children

Aviation has been shown to cause high particle number concentrations (PNC) in areas surrounding major airports. Particle size distribution and composition differ from motorized traffic. The objective was to study short-term effects of aviation-related UFP on respiratory health in children.In 2017–2018 a study was conducted in a school panel of 7–11 year old children (n = 161) living North and South of Schiphol Airport. Weekly supervised spirometry and exhaled nitric oxide (eNO) measurements were executed. The school panel, and an additional group of asthmatic children (n = 19), performed daily spirometry tests at home and recorded respiratory symptoms. Hourly concentrations of various size fractions of PNC and black carbon (BC) were measured at three school yards. Concentrations of aviation-related particles were estimated at the residential addresses using a dispersion model. Linear and logistic mixed models were used to investigate associations between daily air pollutant concentrations and respiratory health.PNC20, a proxy for aviation-related UFP, was virtually uncorrelated with BC and PNC50-100 (reflecting primarily motorized traffic), supporting the feasibility of separating PNC from aviation and other combustion sources. No consistent associations were found between various pollutants and supervised spirometry and eNO. Major air pollutants were significantly associated with an increase in various respiratory symptoms. Odds Ratios for previous day PNC20 per 3,598pt/cm3 were 1.13 (95%CI 1.02; 1.24) for bronchodilator use and 1.14 (95%CI 1.03; 1.26) for wheeze. Modelled aviation-related UFP at the residential addresses was also positively associated with these symptoms, corroborating the PNC20 findings. PNC20 was not associated with daily lung function, but PNC50-100 and BC were negatively associated with FEV1.PNC of different sizes indicative of aviation and other combustion sources were independently associated with an increase of respiratory symptoms and bronchodilator use in children living near a major airport. No consistent associations between aviation-related UFP with lung function was observed.

Fractional exhaled nitric oxide, a potential biomarker for evaluating glucocorticoids treatment and prognosis in allergic bronchopulmonary aspergillosis

BackgroundAllergic bronchopulmonary aspergillosis (ABPA) is characterized by enhanced TH2 inflammatory response. Fractional exhaled nitric oxide (FeNO) measurement has been used as a valuable tool in predicting the development and management of asthma, another typical TH2 inflammation. However, the clinical significance of FeNO in ABPA remains unclear. ObjectiveTo investigate the association between FeNO and the prognosis of patients with ABPA to provide a basis for the use of FeNO in evaluating the efficacy of glucocorticoids in ABPA treatment. MethodsThis study comprised 2 parts; 58 patients were enrolled in the retrospective study. Clinical indexes in patients with different prognoses were compared, and receiver operating characteristic curve analysis was used to determine the threshold value. The prospective observational study involved 61 patients who were regularly followed up at 4 to 6 weeks and 6 months since the initial treatment. Patients were grouped on the basis of baseline FeNO values; correlation analysis was performed in the clinical data. ResultsDifferent prognoses were observed between patients with high and low baseline FeNO values, with a threshold value of 57 parts per billion. The percentage of Aspergillus fumigatus-specific IgE, percentage of positive A fumigatus-specific IgG, and relapse/exacerbation rate differed significantly between the high and low FeNO groups. Patients with higher FeNO needed longer treatment duration and showed shorter interval between glucocorticoid withdrawal and the next relapse/exacerbation. ConclusionOur findings indicate that the level of FeNO is associated with the prognosis of ABPA. It can serve as an independent and valuable biomarker for evaluating the effectiveness of glucocorticoid treatment.

The diagnostic impact of fractional exhaled nitric oxide for asthmatic cough in nontuberculous mycobacterial pulmonary disease.

Measurement of exhaled nitric oxide (FeNO) is a potentially useful diagnostic test for asthma. However, no study has explored the relationship between FeNO and respiratory symptoms of nontuberculous mycobacterial pulmonary disease (NTM-PD) complicated with asthma. The objective of this study was to assess the utility of measuring FeNO levels in patients with NTM-PD complicated by asthma. In this single-center retrospective cohort study, 140 NTM-PD patients with FeNO measured were enrolled. We selected NTM-PD patients who complicated with asthma as the NTM+BA group, defined using the following criteria: NTM patients with symptoms consistent with asthma, and NTM patients with symptomatic improvement after diagnostic therapy with ICS ± a long-acting beta 2-agonist (LABA). We then calculated a diagnostic cutoff point to distinguish between the NTM+BA groups and the NTM groups (all others). High-resolution computed tomography (HRCT) images were evaluated using the CT scoring system and their association with FeNO was examined. A total of 89 patients were included in the study. (31 in the NTM+BA group and 58 in the NTM group). Compared with the NTM group, the NTM+BA group had higher rates of allergic disease (51.6% vs. 22.4%; p=0.0085) and higher FeNO values (median, 23 [interquartile range {IQR}, 15.0-43.0] ppb vs. median, 17 [IQR, 11.8-23.0] ppb; p=0.015). With diagnostic asthma care using mainly ICS/LABA with reference to the FeNO, most patients (91.0%, 20/22) in the NTM-preceding subgroup in the NTM+BA group demonstrated a prompt improvement of their symptoms and AFB culture findings did not worsen (Culture positive rate (%): Pre-treatment: 59.1% vs. Post-treatment: 40.9%, p=0.3660) at 6 months after starting diagnostic therapy. The optimal diagnostic cutoff point of FeNO to distinguish between the two groups was calculated as 21.5 ppb by the ROC curve (sensitivity 75%, specificity 71.93%, p<0.0001; area under the curve: 0.7989). No significant correlation was observed between FeNO and the severity of CT images in the patients. A certain number of patients with NTM-PD showed exacerbated respiratory symptoms due to asthmatic complications. Elevated FeNO levels suggest asthma complications, even in patients with NTM.

Fractional exhaled nitric oxide distribution and its relevant factors in the general adult population and its healthy subpopulation

Measurement of fractional exhaled nitric oxide (Feno) has been used in the diagnosis and management of asthma. Understanding the distribution of Feno in a larger resident population and its "healthy" subpopulation would contribute to the interpretation of Feno in clinical practice. This study aimed to investigate the distribution and its associated factors in the adult population and its healthy subpopulations. We conducted a cross-sectional study of 8,638 men and 17,288 women aged 20 years or older living in Miyagi prefecture, Japan. We investigated the distribution of Feno and its associated factors in all subjects, a subpopulation with no history of upper and lower airway diseases (healthy subpopulation 1), and a subpopulation with no history of upper and lower airway diseases, normal lung function, and no positivity for other biomarkers of type 2 inflammation (healthy subpopulation 2). The distribution of Feno in healthy subpopulations, especially in healthy subpopulation 2 (median [interquartile range], 17 [12-23] with 95th percentile of 36 ppb) was lower than in all subjects (19 [13-26] ppb with 95th percentile of 47 ppb). In healthy subpopulation 1, 10.3% had elevated Feno (≥35 ppb), and elevated Feno was positively associated with factors including obstructive ventilatory defect, blood eosinophilia, house dust mite-specific IgE positivity, and history of hypertension. Male sex was associated with elevated Feno in all subjects and healthy subpopulations. The distribution of Feno in the healthy subpopulation supports the validity of the criteria (≥35 ppb) currently used in Japan for the diagnosis of asthma.

Elevated Saliva Pepsin Concentration as a Risk Factor for Asthma in Children with Allergic Rhinitis: A Preliminary Study.

This study aimed to explore whether saliva pepsin concentration (SPC) could be regarded as a risk factor for the occurrence and unfavorable control of asthma in children with allergic rhinitis. A prospective study was conducted on a group of 20 consecutive children newly diagnosed with allergic rhinitis and asthma (referred to as the asthma group). All these children underwent fractional exhaled nitric oxide (FeNO) measurement, lung function tests, and assessment of asthma control using the 7-item Childhood Asthma Control Test (C-ACT) score. Simultaneously, a control group consisting of 20 children with simple allergic rhinitis, matched for baseline characteristics, was included. SPC measurement was performed in the two groups. The SPC value was significantly higher in the asthma group than that in the control group (165.0 ± 82.8 ng/mL vs 68.4 ± 34.5 ng/mL) (P < 0.001). In the asthma group, SPC was independently associated with FeNO, the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC), and forced expiratory flow at 50% and 75% of FVC (FEF50 and FEF75) (all P < 0.05). The severity of nasal symptoms evaluated by the visual analogue scale (N-VAS) was independently associated with FEF75, the maximal mid-expiratory flow (MMEF), and C-ACT score (P < 0.05). Direct pepsin exposure and uncontrolled nasal symptoms may play crucial roles in the pathogenesis and progression of childhood allergic asthma. The SPC value can be considered as a risk factor for asthma in children with allergic rhinitis.

Diagnosis and therapy of patients with asthma in Germany. Results of the care study RELEVANT

Diagnostic and therapeutic options for asthma have improved with asthma control and remission being of central importance. The RELEVANT study aimed for a nationwide snapshot of current asthma diagnosis and treatment in general practice and specialty care for identification of further aspects for optimization. RELEVANT is a nationwide cross-sectional study using a structured questionnaire. This comprised 14 questions on asthma-related topics covering diagnostics and therapy. Participants were general practitioners/internal medicine specialists and pulmonologists. A total of 1,558 persons took part in the survey. Regarding relevant specific diagnostic procedures for asthma, GPs/internists almost exclusively mentioned pulse oximetry. Among the pulmonologists, fractional exhaled nitric oxide (FeNO) measurement was mentioned, among others. FeNO and blood eosinophils were only mentioned by the pulmonologists as diagnostic and treatment-relevant markers. A total of more than 60% of the GPs/internists surveyed stated that only around 25% or fewer of their patients would voluntarily report restrictions in their everyday lives. Regarding drug treatment, the majority stated that they recognized differences between various ICS/LABA combination therapies. The results indicate a need for optimization, particularly regarding asthma control. This involves both a better assessment by patients' everyday life restrictions and modern ways of assessing asthma control in cooperation between GPs/internal medicine specialists and pulmonologists. One fifth of respondents do not see any differences between various ICS/LABA combinations in daily practice, although there are pharmacodynamic and pharmacokinetic differences.

Total airway mechanics and fractional exhaled nitric oxide levels of children living in banjihas (semi-basements).

The ISAAC phase III study in Korea found a higher incidence of wheezing illnesses among residents in basements or semi-basements. This study investigates the link between living in banjihas (semi-basements) and airway resistance and Th2 airway inflammation in Korean children, compared to those on higher floors. We assessed 575 fifth- and sixth-grade students (aged 10-12) in an inner-city area of South Korea. The study utilized impulse oscillometry to measure small and total airway resistance (Rrs20-5 and Rrs0, respectively) and Fractional Exhaled Nitric Oxide (FeNO) measurements to evaluate airway inflammation. We also considered a range of biological and environmental factors, including allergen sensitization, serum 25-hydroxyvitamin D levels, and urinary metabolites like VOCs, bisphenol, and triclosan. Participants were categorized by living floors: banjihas, first-fifth floors, and sixth floors or higher. Twenty-five children (4.3%) lived in banjihas, 311 (54.1%) on the first to fifth floor, and 239 (41.6%) on the sixth floor or above. Despite similar levels of allergen sensitization and urinary pollutant metabolite levels across all groups, banjiha dwellers showed significantly higher total airway resistance (adjusted &1: 0.633, 95%CI: 0.156, 1.109; P = 0.009) and a greater prevalence of elevated FeNO levels (> 35 ppb) (P = 0.033). These findings persisted after adjusting for critical factors like height, gender, BMI z-score, and birth conditions. Children in banjihas exhibit elevated airway resistance and FeNO levels independently of allergen sensitization or pollution exposure, underscoring the necessity for enhanced focus on their respiratory health in such living conditions.

Association of inflammatory cytokines with obesity and pulmonary function testing.

The World Health Organization (WHO) reported that the prevalence of obesity in the Kingdom of Saudi Arabia (KSA) is 33.7% (women 39.5% and men 29.5%), respectively. The effects of obesity on airway inflammation and respiratory mechanics as well as the function of adipose tissue has a key role in the development of various lung diseases. Therefore, this study aimed to compare the level of cytokines between obese (BMI ≥ 30) and non-obese participants and to assess their association with BMI, airways inflammation and pulmonary function. One-hundred and seven non-smoking students (18-25 years of age) were recruited using convenience sampling technique for comparative cross-sectional study. Of them, 80 students were eligible and included in the analysis; 54 were non-obese (BMI<30) and 26 were obese (BMI ≥ 30). All the participants underwent anthropometric measurements, fractional exhaled nitric oxide (FeNO) measurement, spirometry and cytokines measurement (IL-6, IL-1β, GM-CSF, IL-7, IL-8 and IL-10). Measurements were compared between obese and non-obese groups. Then a correlation test was made between pro- and anti-inflammatory cytokines with BMI, pulmonary function test finding and FeNO. The prevalence of obesity was 32.5% in the study population. Levels of pro-inflammatory cytokine IL-6 levels was significantly higher in obese than non-obese participants (p = 0.044). The level of FeNO log was significantly higher in obese participants than non-obese (p = 0.002). The pro-inflammatory cytokine IL-6 showed positive correlation with BMI while GMCSF showed negative correlation with FVC (p<0.05). The levels of pro-inflammatory cytokine IL-6 was found to be significantly higher in obese participants than non-obese participants. Furthermore, it showed positive correlation with BMI whereas pro-inflammatory cytokine GMCSF showed negative correlation with FVC.

A miniaturized photodiode-based chemiluminescence sensor for measurement of fractional exhaled nitric oxide

Fractional exhaled nitric oxide (FENO) measurement is a valuable tool in diagnosing and monitoring certain respiratory diseases, low cost and miniaturized NO sensor is highly demanded for FENO home healthcare self-monitoring. In this work, a miniature photodiode-based chemiluminescence sensor is presented for the sensitive measurement of NO concentration. Effects of various reflective film materials including stainless-steel, aluminum and silver for coating the inner surface of the optical cell were investigated for higher photon collection efficiency, and the silver reflective film displayed the best sensitivity. As the oxidation and pollution of silver film led to dramatical decay of signal, a quartz inner chamber with reflectance film layer coated on its outer surface was developed to achieve high stability and sensitivity simultaneously. The limit of detection for FENO was 6.6 ppb, the linear range of 10–100 ppb with a response time of 6.8 s was reached, which was satisfied the requirements for FENO measurement. The weight of the sensor is 96 g with a size of only 6.5 × 3 × 2 cm3, and the cost is estimated less than $1 K, which is suit for on-site monitoring of FENO. FENO50 was obtained the response difference of room air and breath air measured successively with a switching valve, the beath air was sampled into a bag at flow rate of 50 ml/s by offline sampling device, and multiple measurements were executed for better accuracy. The potential usage of the sensor was further illustrated by studying the FENO50 levels of individuals before and after consuming nitrate-rich sports drinks.

Effect of infant viral respiratory disease on childhood asthma in a non-industrialized setting.

There are limited data from non-industrialized settings on the effects of early life viral respiratory disease on childhood respiratory illness. We followed a birth cohort in tropical Ecuador to understand how early viral respiratory disease, in the context of exposures affecting airway inflammation including ascariasis, affect wheezing illness, asthma, and rhinoconjunctivitis in later childhood. A surveillance cohort nested within a birth cohort was monitored for respiratory infections during the first 2years in rural Ecuador and followed for 8years for the development of wheeze and rhinoconjunctivitis. Nasal swabs were examined for viruses by polymerase chain reaction and respiratory symptom data on recent wheeze and rhinoconjunctivitis were collected by periodic questionnaires at 3, 5, and 8years. Stools from pregnant mothers and periodically from children aged 2years were examined microscopically for soil-transmitted helminths. Atopy was measured by allergen skin prick testing at 2years. Spirometry, fractional exhaled nitric oxide measurement, and nasal washes were performed at 8years. Associations between clinically significant respiratory disease (CSRD) and wheezing or rhinoconjunctivitis at 3, 5, and 8years were estimated using multivariable logistic regression. Four hundred and twenty six children were followed of which 67.7% had at least one CSRD episode; 12% had respiratory syncytial virus (RSV)+CSRD and 36% had rhinovirus (RHV)+CSRD. All-cause CSRD was associated with increased wheeze at 3 (OR 2.33 [95% confidence intervals (CI) 1.23-4.40]) and 5 (OR: 2.12 [95% CI 1.12-4.01]) years. RHV+CSRD was more strongly associated with wheeze at 3years in STH-infected (STH-infected [OR 13.41, 95% CI 1.56-115.64] vs. uninfected [OR 1.68, 95% CI 0.73-3.84]) and SPT+ (SPT+ [OR 9.42, 95% CI 1.88-47.15] versus SPT- [OR 1.92, 95% CI 0.84-4.38]) children. No associations were observed between CSRD and rhinoconjunctivitis. CSRD was significantly associated with childhood wheeze with stronger associations observed for RHV+CSRD in SPT+ and STH-infected children.

Age-related differences in associations between uncontrolled asthma, comorbidities and biomarkers in adult-onset asthma

Objective Adult-onset asthma is a recognized but heterogeneous phenotype and has been described to associate with poor asthma control. Knowledge about associations between clinical characteristics including comorbidities and control of adult-onset asthma is limited, especially in older populations. We aimed to study how clinical biomarkers and comorbidities are associated with uncontrolled asthma among middle-aged and older individuals with adult-onset asthma. Methods Clinical examinations including structured interview, asthma control test (ACT), spirometry, skin prick test (SPT), blood sampling, and measurement of exhaled fractional nitric oxide (FeNO) was performed in a population-based adult-onset asthma cohort in 2019–2020 (n = 227, 66.5% female). Analyses were performed among all included, and separately in middle-aged (37–64 years, n = 120) and older (≥65 years, n = 107) participants. Results In bivariate analysis, uncontrolled asthma (ACT ≤ 19) was significantly associated with a blood neutrophil count ≥5/µl, BMI ≥30, and several comorbidities. In multivariable regression analysis, uncontrolled asthma was associated with neutrophils ≥5/µl (OR 2.35; 95% CI 1.11–4.99). In age-stratified analysis, BMI ≥30 (OR 3.04; 1.24–7.50), eosinophils ≥0.3/µl (OR 3.17; 1.20–8.37), neutrophils ≥5/µl (OR 4.39; 1.53–12.62) and allergic rhinitis (OR 5.10; 1.59–16.30) were associated with uncontrolled asthma among the middle-aged. Among the older adults, uncontrolled asthma was only associated with comorbidities: chronic rhinitis (OR 4.08; 1.62–10.31), ischemic heart disease (OR 3.59; 1.17–10.98), malignancy (OR 3.10; 1.10–8.73), and depression/anxiety (OR 16.31; 1.82–146.05). Conclusions In adult-onset asthma, comorbidities were strongly associated with uncontrolled asthma among older adults, while clinical biomarkers including eosinophils and neutrophils in blood were associated with uncontrolled asthma among middle-aged.

Anxiety and depression in women with asthma prior to fertility treatment

ABSTRACT Objective We investigate symptoms of anxiety and depression among women with asthma prior to fertility treatment. Methods This is a cross-sectional study of women screened for eligibility to the PRO-ART study (RCT of omalizumab versus placebo in asthmatic women undergoing fertility treatment (NCT03727971)). All participants were scheduled for in vitro fertilization (IVF) treatment at four public fertility clinics in Denmark. Data on demographics and asthma control (ACQ-5) were obtained. Symptoms of anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS-A and D, respectively) and defined as being present on both subscales if a score >7 was obtained. Spirometry, diagnostic asthma test, and measurement of fractional exhaled nitric oxide (FeNO) were conducted. Results A total of 109 women with asthma were included (mean age 31.8 ± 4.6 and BMI 25.5 ± 4.6). Most women had male factor infertility (36.4%) or unexplained infertility (35.5%). Twenty-two percent of the patients reported uncontrolled asthma (ACQ-5 score > 1.5). The mean HADS-A and HADS-D scores were 6.0 ± 3.8 (95% CI 5.3–6.7) and 2.5 ± 2.2 (95% CI 2.1–3.0), respectively. Thirty (28.0%) women reported anxiety symptoms, and four (3.7%) had concomitant depressive symptoms. Uncontrolled asthma was significantly associated with both depressive (p = 0.04) and anxiety symptoms (p = 0.03). Conclusions More than 25% of women with asthma prior to fertility treatment had self-reported symptoms of anxiety, and just below 5% had self-reported depressive symptoms, possibly related to uncontrolled asthma.

Serial fractional exhaled nitric oxide measurements at and off work may help to identify immunologic occupational asthma in cases with complex exposures

Serial measurements of fractional exhaled nitric oxide (FeNO) at home and at work have been described to provide complementary information for the diagnosis of occupational asthma (OA) when specific inhalation challenge (SIC) is missing or doubtful. We describe two cases in which serial FeNO measurements enabled the detection of probable OA after complex exposures. A 25-year-old industrial painter with exposure to a variety of paints suffered from work-related airway symptoms for five years. Lung function was normal, and she was not atopic. SIC with hexamethylene diisocyanate was negative. A 47-year-old sign maker (screen printing, foils) suffering from work-related dyspnoea for seven years. Moderate airway obstruction, but no atopy was detectable. Due to the complex exposures SIC was not performed. Both patients performed FeNO measurements once daily during a 2–week-holiday and a subsequent 2–week-work period. In both cases elevated baseline FeNO decreased to normal (25 ppb) during holidays and increased after resuming work (case 1: 125 ppb, case 2: 45 ppb).

A hierarchical cluster analysis of the psycological impact of the COVID-19 pandemic on Italian severe asthma patients

Introduction In the context of COVID-19 pandemic, a consistent medical concern raised among severe asthma patients, though the studies excluded an increased risk of severe disease as well as an increased susceptibility. The aim of the study was to apply the Psychological General Well-Being Index (PGWBI) questionnaire to severe asthmatics during the COVID-19 pandemic and to evaluate the data with a hierarchical cluster analysis. Methods 114 severe asthmatics were asked to respond anonymously to the PGWBI questionnaire. The patients underwent a lung functional test, fractional exhaled nitric oxide (FeNO) measurement, Asthma Control Test (ACT), and Asthma Control Questionnaire (ACQ6). A hierarchical cluster analysis was performed using an agglomerative approach and complete linkage to evaluate the results. Results The study population predominantly included female (60%), middle-aged patients, with normal lung function parameters, mild signs of airway, and satisfactory asthma control. The PGWBI score (82.46 ± 16.53) of the study population showed a good state of psychological well-being and was similar to that of a representative sample of healthy adult Italian subjects. Thus, Hierarchical cluster analysis identified 3 groups of patients: Cluster 1 (32%), Cluster 2 (64%), and Cluster 3 (4%). Whilst the Cluster 2 patients’ PGWBI score fell within the normal range, the Cluster 1 patients had a significantly lower total score (68.57 ± 7.2; p < 0.05), suggesting moderate distress. The Cluster 3 patients presented a total score markedly low. Conclusion Although the majority of the severe asthma patients studied demonstrated good mental well-being during the COVID-19 pandemic, some did indeed show moderate to severe psychological distress.

Effect of Obesity on Airway Mechanics.

Obesity is known to induce lung function impairment. Previous studies of decline in lung function associated with obesity are well established. In this cross-sectional study, to evaluate the effects of different obesity indices on lung mechanics, healthy subjects (males-23 and females-22) were recruited. Anthropometric parameters like body mass index (BMI), waist circumference (WC), hip circumference (HC) and neck circumference (NC) were measured and waist-hip ratio (WHR) was derived. Spirometry, impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) measurements were performed to assess lung function. Subgroups were divided and analysed. In males, increased WHR is associated with increased total airway resistance (R5). BMI correlates positively with R5, R5% predicted, resistance at 20 Hz (R20) and R20% predicted; likewise, WHR shows a positive correlation with R5. In females, increased WHR has significantly higher R5, R5% predicted, R20, R20% predicted, area of reactance (Ax), resonant frequency (Fres) and decreased reactance at 5 Hz (X5), reactance at 20 Hz (X20), X20% predicted. The female group with higher WC shows significantly increased R5, R5% predicted, R20, R20% predicted, Ax, Fres and lower fixed ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC), X5, X20, X20% predicted. The group with higher NC has a lower FEV1/FVC ratio. WHR positively correlated with R5% predicted and Fres while WC correlated positively with R5, R5% predicted, Ax and Fres; same way, NC with X5% predicted. Obesity/overweight causes significant changes in lung volumes, capacity and airway mechanics, Higher WC and WHR are associated with significant changes in lung mechanics, which are more prominent in females than in males. NC is not associated with changes in lung mechanics.

Methacholine and FeNO Measurement in Patients with Habit Cough.

Chronic cough is one of the most common symptoms in childhood. Making a definite diagnosis is a challenge for all pediatricians especially in patients when cough is without an organic cause like in habit cough. In this retrospective analysis, all electronic outpatient charts of the Division of Allergology and Pneumology, between January 1, 2010 and December 31, 2019 were reviewed in order to study all children with potential habit cough. All children underwent the following diagnostic algorithms, skin prick test (SPT), measurement of fractional exhaled nitric oxide (FeNO), spirometry and methacholine challenge test (MCT). The value of a normal MCT and FeNO measurement for diagnosing habit cough was investigated. The chart review revealed 482 patients with chronic cough>4 weeks. Of these, 99 (20.5%) with suspected habit cough were collected. 13 patients had to be excluded for other diagnosis and a complete data set was available in 55 patients. 33 (60.0%) of 55 patients were SPT negative and 22 (40.0%) had sensitization to common allergens. Five patients had elevated FeNO≥20 ppb and three showed severe bronchial hyperresponsiveness<0.1 mg methacholine, challenging the diagnosis of habit cough. A normal FeNO and MCT can help confirm the clinical diagnosis of habit cough. However, in patients with positive MCT and/or elevated FeNO habit cough can be present. Especially in patients with elevated FeNO and severe BHR cough variant asthma and eosinophilic bronchitis have to be ruled out.

Fractional nitric oxide measurement in exhaled air (FeNO): perspectives in the management of respiratory diseases.

Exhaled nitric oxide (NO) production, upregulated by inflammatory cytokines and mediators in central and peripheral airways, can be easily and non-invasively detected in exhaled air in asthma and other respiratory conditions as a promising tool for disease monitoring. The American Thoracic Society and European Respiratory Society released recommendations that standardize the measurement of the fractional exhaled NO (FeNO). In asthma, increased FeNO reflects eosinophilic-mediated inflammatory pathways and, as a biomarker of T2 inflammation can be used to identify asthma T2 phenotype. In this setting its measurement has shown to be an important tool especially in the diagnostic process, in the assessment and evaluation of poor adherence or predicting positive response to inhaled corticosteroids treatment, in phenotyping severe asthma patients and as a biomarker to predict the response to biologic treatments. The discovery of the role of NO in the pathogenesis of different diseases affecting the airways and the possibility to estimate the predominant site of increased NO production has provided new insight on its regulatory role in the airways, making it suitable for a potential extended use in clinical practice for different pulmonary diseases, even though its role remains less clear than in asthma. Monitoring FeNO in pulmonary obstructive lung diseases including chronic bronchitis and emphysema, interstitial lung diseases, obstructive sleep apnea and other pulmonary diseases is still under debate but has opened up a window to the role NO may play in the management of these diseases. The use of FeNO is reliable, cost effective and recommendable in both adults and children, and should be implemented in the management of patients with asthma and other respiratory conditions.

Bronchial reactivity to inhaled hypertonic saline solutions in children with cystic fibrosis

Background. Inhaled hypertonic saline solutions (IHSS) are included in the list of mandatory prescriptions in the treatment of cystic fibrosis (CF). However, some patients with CF may develop bronchial hyperreactivity (BHR), which may be the cause of violation of the treatment protocol. The purpose is to study the state of bronchial reactivity to IHSS and its dependence on the clinical, functional and microbiological features of CF course in children. Materials and methods. Forty children with CF were examined. All of them underwent general clinical, molecular genetic, laboratory and microbiological examination. Instrumental methods included spirometry, measurement of fractional exhaled nitric oxide, X-ray and computer tomography of the chest. To determine the individual tolerance of inhalations of hypertonic sodium chloride solution (HSCS), the research protocol proposed by E.P. Dellon et al. was used. Results. According to the results of the research protocol, 17 (42.5 %) patients with CF had BHR to HSCS. The highest frequency of BHR was found in children with a severe CF course. There was no dependence of BHR in CF patients on allergic pathology and a burdened allergic history. Assessment of the tolerance of HSCS before prescribing basic therapy is important. Early functional signs of BHR, which may require the preventive administration of short-acting β2-agonists when using HSCS in children with CF, are as follows: reduction in forced expiratory volume in 1 second by 7 % and maximal expiratory flow at 25 % by 6 % when using 3% HSCS. Conclusions. The presence of BHR in patients with CF may interfere with adequate basic therapy by inhalation. The prescription of IHSS to patients with CF should be personalized with the determination of individual sensitivity of a person to predict a positive therapeutic effect.

Bronchial hyperresponsiveness and asthma during oral immunotherapy for egg or peanut allergy in children.

BackgroundBronchial hyperresponsiveness (BHR) and asthma are frequently present in children with food allergy. We assessed BHR in children receiving oral immunotherapy (OIT) for persistent egg or peanut allergy and examined whether OIT affects asthma control.MethodsMethacholine challenge testing was performed in 89 children with persistent egg or peanut allergy diagnosed by double‐blind, placebo‐controlled food challenge and 80 control children without food allergy. Of the 89 food‐allergic children, 50 started OIT for egg allergy and 39 for peanut allergy. Sensitization to aeroallergens was evaluated by skin prick testing. Forty of the 89 children with regular controller treatment for asthma underwent methacholine challenge testing and 34 measurement of exhaled nitric oxide (FeNO) at baseline and after 6–12 months of OIT.ResultsMethacholine challenge testing revealed significant BHR in 29/50 children (58%) with egg allergy, 15/39 children (38%) with peanut allergy, and 6/80 controls (7.5%). The mean cumulative dose of methacholine causing a 20% fall in FEV1 differed significantly between the egg and peanut‐allergic versus the control children (1009 μg, 1104 μg, and 2068 μg, respectively, p < 0.001). Egg or peanut OIT did not affect lung function, the degree of BHR or FeNO levels in children with asthma and had no adverse effect on asthma control. Lung function or BHR did not associate with the OIT outcome.ConclusionBHR was significantly more frequent in children with persistent egg or peanut allergy than in children without food allergy. Oral immunotherapy did not increase BHR and was safe for children on regular asthma medication.

Importance of measuring Fractional Exhaled Nitric Oxide (FeNO) in the management of asthma

Asthma is characterized by chronic airway inflammation leading to respiratory symptoms (dyspnea, wheezing, chest tightness and cough). So direct measure of the level of inflammation can be of paramount importance in the proper understanding of severity of asthma. Nitric oxide (NO) isa product of inflammation in the airways and an important regulator of immune responses that is overproduced in asthma. For this purpose, the measurement of Fractional Exhaled Nitric Oxide (FeNO) has been used since the early years of the current century as a non-invasive, easy-to-assess tool useful for diagnosing and managing asthma. In this narrative review we extended our effort to explain the usefulness of FeNO as a predictor of response to inhaled corticosteroids (ICSs), to monitor adherence and as a diagnostic tool in asthma management. Bangladesh J Medicine 2022; 33: 241-246